Cathode-input signal-translating arrangement



March 1, 1949. v H, WHEELER GATHODE-INPUT SIGNAL-TRANSLATING ARRANGEMENT 2 Sheets-Sheet 1 Filed June 2, 1944 FIGJ lllll l lil'li.

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WHEELER /flZ ORNEY O HEATER SUPPLY March 1, 1949.

H. A. WHEELER CATHODE-INPUT SIGNAL-TRANSLATING ARRANGEMENT 2 Sheets-Sheet 2 Filed June 2, 1944 FIG. 4 a

INVENTOR Ag-ELER A ORNEY HAR-OL Patented Mar. 1, 1949 CATHODE-INPUT SIGNAL-TRANSLATING ARRANGEMENT Harold A. Wheeler, Great Neck, N. Y., asslgnor, by mesne assignments, to Hazeltine Research, Inc., Chicago, 11]., a corporation of Illinois Application June 2, 1944, Serial No. 538,518

14 Claims. 1

This invention relates to cathode-input signaltranslating arrangements and is particularly directed to such arrangements having a wide range of operating frequencies. While the invention is of general application, it is of particular value when used in a system operating in the ultrahigh-frequency portion of the frequency spectrum. The expression cathode-input signaltranslating arrangement," as used throughout the following description and in the appended claims, is intended to mean a signal-translating arrangement designed to have, under normal operating conditions, a control electrode maintained at a fixed reference potential, such as ground potential, and a cathode having a potential which varies in accordance with an input signal for the arrangement.

As is well understood in the art, a cathodeinput signal-translating arrangement is especially valuable for use as a wide-band amplifier. In such applications, the arrangement generally comprises a conventional triode vacuum tube operated with the control electrode at ground potential. An amplifying stage of the typeunder consideration has the advantage over the more commonly used amplifying stage, where the input signal is applied directly to the control electrode of an amplifying vacuum tube, that the control electrode, being maintained at a fixed reference potential, provides a nearly complete electrostatic shield between the anode and cathode electrodes of the amplifying tube which may minimize the undesirable coupling and regenerative effects within the stage resulting from the interelectrode capacitance between the anode and cathode electrodes.

It will be appreciated that for high-frequency operation optinum results are obtained only if the capacitance between the input and output circuits of the stage is reduced to a minimum so that there is substantially no regeneration or undesired capacitive coupling in the amplifying circuit. However, it is found that in cathode-input arrangements of the type heretofore known in the art the desirable shielding eiiect of the control electrode is lessened by undesirable capacitances existing within the amplifying tube and by other undesirable capacitances of the arrangement external to the tube. The firstmentioned undesirable capacitance may have one component contributed by the leads connecting the anode and cathode electrodes to the terminal prongs of the tube base and another component consisting of a capacitance between corresponding end portions of the anode and cathode elecdesirable capacitances limits the maximum operating frequency of the cathode-input arrangement, thereby unduly restricting its operatingfrequency range.

Amplifying arrangements utilizing vacuum tubes constructed in such a manner that a shielding effect is incidentally obtained between certain of the electrode leads and tube prongs are known. In one arrangement of the type referred to, the tube base includes four terminal prongs positioned at the corners of a square; the cathode is of the directly heated filament type and is con-- nected through a pair of electrode leads to a pair of diagonally opposed terminal prongs; an electrode lead connects the anode with a terminal prong located on one side of the diagonally opposed prongs, while another electrode lead connects the control electrode with the terminal prong on the opposite side of the diagonally opposed prongs. In other Words, the electrode leads and terminal prongs connected with the cathode are intermediate the electrode leads and terminal prongs connected with the anode and control electrodes and thus partially shield the leads and prongs of the anode and control electrodes. However, the described arrangement is not suited for the high-frequency cathode-input application under consideration since the oathode electrode is connected with the intermediate prongs of the tube base and, obviously, does not provide a shield between the anode and cathode electrode leads and prongs, as is required to prevent undesired regenerative efiects in a cathodeinput arrangement.

It is an object of the invention, therefore, to provide a cathode-input signal-translating arrangement which avoids one or more of the above-mentioned limitations of prior art arrangements.

It is another object of the invention to provide an improved cathode-input signal-translating arrangement having a wide range of operating frequencies, preferably in the ultra-high-frealso has a single control electrode positioned between the anode and cathode as well as a conductive shield structure connected to the control electrode and positioned substantially intermediate all conductive elements connected to the anode and all conductive elements connected to the cathode.- The'shield structure comprises at least one electrode lead extending in the aforesaid direction.

For a better understanding of the present invention, together with other and further objects thereof, reference is had to the following description taken in connection with the accompanying drawings, and its scope will be pointed out in the appended claims.

Referring to the drawings, Figs. 1 and 2 are schematic representations of difierent embodiments of a cathode-input signal-translating arrangement in accordance with the invention; Fig. 3 represents a socket arrangement suitable for use with the embodiment of Fig. 2; Fig. 4a is a cross-sectional view, partially broken away, of a further embodiment of the invention; Fig. 4b is a sectional view taken along the line indicated by directional arrows A-A of Fig. 46; Fig. 5a is a View in partial cross section of a still further embodiment of the invention; while Figs. 5b and 5c are cross-sectional views taken, respectively, as indicated bythe directional arrows BB, and CC of Fig. 5a; Fig. 5d is a perspective view, partly broken away, of the top portion. of the electrode structures of the Fig. 5a arrangement showing the construction of an upper shield cap; Fig. 5e is a perspective view of a lower shield cap included in the arrangement of Fig. 5a; and Fig. 6 is a schematic circuit diagram including a cathode-input signal-translating arrangement in accordance with the invention.

Referring now more particularly to Fig. 1 of the drawings, there is represented schematically and in simplified form a cathode-input signaltranslating arrangement constructed in accordance with the teachings of the present invention. The arrangement comprises a single-ended multielement electron-discharge device, specifically a triode vacuum tube, having an envelope I0 partially broken away to reveal the electrode structures contained therein. A terminal structure, press or base II is formed integrally with: and illustrated as part of'envelope Ill. Three closely spaced terminal means or prongs I2, I3 and I4 for making circuit connections to the arrangement are included in base II, projecting therethrough and being suitably sealed in conventional manner. As shown, prongs I2, I3 and I4 are arranged in .alignment with prong I3 directly beprong I4. A planar control electrode I9 is 130- sitioned .between the anode and cathode electrodes, being disposed in parallel relationship with respect thereto. The control electrode is of a well-known construction and comprises a pair of supporting rods which support a spiral-type winding. The winding portion in the space between the supporting rods constitutes a portion of the control electrode which is effective to control electron flow between anode I5' and cathode II. The cathode heater element and electrode supporting devices conventionally included in electron-discharge devices of the type under consideration have been omitted from the drawings in order to simplify the disclosure of the invention.

The anode and cathode structures tend to have an undesirable capacitance between portions thereofwhich are substantially una'ssociated with the above-described control portion of the control electrode. For the simplified embodiment under consideration, these portions comprise the leads I6 and I8 of the anode and cathode structures, respectively. Similarly, terminal prongs I2 and I4 tend to provide an undesired capacitance between the anode and cathode structures. The cathode-input arrangement is provided with means conductively connected with the control 40 electrode I9 and physically positioned with reference to the aforesaid portions of the anode'and cathode structures-to provide an electrostatic shield between such portions and between terminal prongs I2 and I4, thereby to minimize the tendency of such portions and such terminal prongs to provide an undesirable capacitance which is effectively between the anode and cathode electrodes. This last-named means comprises an electrode lead 20 conductively connecting control electrode I9 to terminal prong I3. Preferably, lead 20 has a physical length approximatelyequal to the shortest distance between the control electrode and terminal prong I3 and- .is physically positioned so as to be in directalignterminal prong I4 while the translated. signalis obtained across a load impedance coupled to prong I2. In the operation of the arrangement,

' the control electrode I9, being maintained at a fixed reference potential as indicated, functions as an electrostatic shield and largely reduces the direct capacitance between anode I5 and cathode II. However, the interstices of-the individual turns of the control electrode provide the essential direct coupling between anode I5 and cathode I I required to sustain and control electron flow therebetween. Furthermore, because of the described orientation oi the electrode leads and sired capacitances resulting from the usual electrode lead and terminal prong arrangements are greatly minimized or substantially eliminated in the described arrangement, permitting a wider range of operating frequencies.

In the described embodiment electrode lead 20 and terminal prong l3 are in direct alignment with the remaining leads l6 and I8 and prongs l2 and I4. While this represents the preferred arrangement, some shielding of undesired capacitances effectively between anode I and cathode I! may be realized where the electrode leads and terminal prongs do not fall in direct alignment.

To achieve the desired result, it is only necessary that the lead and terminal prong associated with the control electrode be substantially intermediate those connected with the anode and cathode electrodes. More particularly, some desired shielding results with an arrangement such that the lead and terminal prong of the control electrode lie within a circular boundary which has a diameter equal to the spacing between corresponding elements of the anode and cathode. Accordingly, the expression physically positioned substantially intermediate said anode and cathode leads and like expressions of the appended claims are intended to designate an arrangement having the foregoing limiting boundary condition.

The cathode-input arrangement of Fig. 2 is generally similar to that of Fig. 1 and corresponding elements thereof are identified by like reference numerals primed. In Fig. 2, the cathode electrode I1 is of the indirectly heated type hav-' ing a filamentary heater 30 shown in broken-line construction. The terminal base ll includes at least four closely spaced terminal prongs or leads for making circuit connections to the arrangement, arranged with a pair of prongs which are connected with the control electrode substantially intermediate two of the remaining prongs connected, respectively, with the anode and cathode electrodes. As illustrated, base ll includes eight prongs arranged in a circular pattern. Of these, prongs l3, l3, which are substantially diametrically opposed, are connected with control electrode or grid I9 by means of an electrode-lead structure presently to be described; prongs I 2', i2, located on the anode side of pair [3, I3, are connected with anode l5 through a pair of leads l6, l6; while the remaining prongs, which are positioned on the cathode side of pair [3, I3, are connected with cathode ii. That is, prongs i4, M are connected directly with cathode H by way of leads l8, l8 and prongs 3|, 3i are connected with heater 30 through leads 32, 32.

The electrode-lead structure conductively -consupporting devices have been omitted to simplify the illustration.

The shielding effect obtained with the arrangement of Fig. 2 in accordance with the invention for the purpose of substantially eliminating undesirable capacitance between the anode and cathode structures will be apparent from the preceding description, Also, it will be'evident to those skilled in the art that the Fig. 2 arrangement is especially suited for operation over a wide band of ultra-high frequencies. It will be noted, for example, that the double electrode leads provided for each of the several electrodes reduces the lead impedances of the arrangement and permits efiicient high-frequency operation.

The conductive plate 33 included in the electrodelead structure associated with control electrode l9 not only minimizes the impedance of the structure but also enhances the shielding eil'ect provided between the electrode leads connected with the anode and cathode electrodes.

The socket arrangement of Fig. 3 is designed for use with the arrangement of Fig. 2 and, consequently, is provided with a plurality of sockets 34-, inclusive, corresponding in number and orientatio'r with the terminal prongs of the oathode-input arrangement. The socket contains a conductive plate 42 extending diametrically thereacross and arrangedto include socket elements 35 and 40 which receive prongs l3, l3 of the control-electrode st='ucture. When the arrangement of Fig. 2 is received by the socket of Fig. 3, plate 42 effectively constitutes an extension of conductive plate 33 and increases the shielding effect of the cathode-input arrangement relied upon for reducing to a minimum undesired capacitances of the anode and cathode structures.

The embodiment illustrated in Figs. 4a and 4b of the drawings is very similar to that of Fig. 2 and corresponding components thereof are designated by the same reference numerals. In the instant arrangement, however, the electrode elements have a generally cylindrical configuration and are positioned in a familiar concentric arrangement. Shielding of the leads and terminal prongs associated with the anode and cathode electrodes is again achieved by having the electrode leads and prongs associated with the control electrode substantially intermediate those of the anode and cathode.

All of the embodiments thus far discussed are represented schematically in the drawings to facilitate illustrating the orientation of the electrodes, their leads and associated terminal prongs in accordance with the principles of the invention. For this reason, those elements usually included within the tube arrangement for mechanically supporting the electrode elements thereof and for providing mechanical rigidity have been omitted from the drawings, as mentioned above. These additional elements are represented in the embodiment of Figs. 5a, 5b, 5c, 5d and 5c.

The cathode-input arrangement of this embodiment is similar to that of Figs. 4a and 4b in that its electrodes have an approximately cylindrical configuration and are concentricall arranged. It comprises an envelope 5!] having an integral terminal base 5! including a plurality of closely spaced terminal prongs 52-58, inclusive, arranged in a generally circular pattern. Each of the several prongs is suitably sealed to the base as indicated. The anode structure includes an anode electrode formed of a pair of U-shaped electrode elements 60, 6| arranged in spaced-opposed relation and interconnected by 7 means of a pair of conductive straps 82, 63 secured midway of the individual electrodes 68, 6|. At its opposing ends each electrode element 68.

9| has a projection 68 received by apertures provided in spaced-insulating discs 65. 66 which support and maintain the desired relative position of the electrode structures within envelope 59. The anode electrode 60, 6| is conductively connected with terminal prongs 52, 58 byway ofelectrode leads 81, 61.

The cathode structure includes an indirectly heated cathode 68 connected by a rigid lead 69 to prong 56 and having a heater element connected with prongs 55, 56 through rigid leads i8, 19.

The electrode element 58 is partially broken away in Fig. a to reveal the control electrode H positioned between the anode and cathode electrodes. The control electrode has a winding portion between the spaced discs 65, 66 for controlling electron flow between the anode and cathode electrodes. The winding support rods of the control electrode project through apertures of the spaced discs and are thus secured in proper position. A conductive element 12, in the form of a grid cap shown separately in Fig. 5d, is conductively connected with the upper portions of thewinding support rods projecting beyond upper spacer disc 65. This cap element eflectively comprises an extension of the control electrode which is physically positioned between and, preferably, extends beyond the corresponding end portions of anode 68, Bi and cathode 68- to provide an electrostatic shield therebetween. A similar conductive cap element 13, illustrated in the perspective view of Fig. 5e, is conductively connected to the lowerportions of the winding cathode-input signal-translating arrangement in' accordance with the invention. The arrangement is a two-stage cathode-input amplifying system including a pair of triode vacuum tubes 89 and 8| which, though represented schematically, are preferably arranged as disclosed in Figs. 5a, 5b and 5c. The cathode circuit of tube 89 includes a self-biasing resistor 8|, by-passed for radiofrequency signals by a condenser 82, and a tuned circuit including an inductor83 and a parallelarranged adjustable condenser 84. An input circuit for applying signals to the amplifying system is provided by a coaxial cable 85 connected I2, 13 are substantially rectangular in cross section. Two opposing sides of the lower cap 13 are provided with formed projections 14 which extend over and are connected with opposed terminal prongs 53, 51, thereby serving as electrode leads for the control-electrode structure. A horizontal projection 15 of one of the remaining sides of cap 13 shields cathode leads 69 and I0 from electrode element 6| of the anode structure which is positioned immediately thereabove. A vertical extension iii of the remaining side of cap 13 is located directly in front of the anode leads 61, 61 and the upper projection of anode prongs 52, 58 further to shield these elements from the cathode structure, its leads and terminal prongs. A supporting pedestal I1 is aflixed to the lower end of projection 16 and rests upon tube base 5| within the circle of terminal prongs. This pedestal supports the control electrode structure. If desired, an additional support may be included, extending from cap element 12 to the crown of envelope 59.

In the embodiment of the invention just described, the electrode lead and terminal prong arrangement is such as to provide a shielding.

with a tap 86 of inductor 88, the tap being adjustable in order to obtain a desired impedance match in the input circuit. A second tuned circuit, provided by an adjustable condenser 81 and the outer winding of a bifilar coil 88, is coupled to the anode electrode of tube 88 through a condenser 89 and is coupled to the cathode electrode of tube 8| through a biasing circuit including the parallel combination of a resistor- 99 and a'by-pass condenser 9|.

Tuned circuit 81, 88 thus couples tubes 89' and 8| in cascade. A third tuned circuit, consisting of an adjustable condenser 92 and the other winding of bifilar coil 93, is coupled to the anode electrode of tube 8| through a condenser 9 An output circuit is provided by a coaxial cable 95 coupled to an adjustable tap 96 of circuit 92, 93. i The control electrodes of tubes 88 and 8| are established at ground potential through leads 91 and 98, respectively, which are physically positioned to be substantially intermediate the circuit elements connected with the anode and cathode, electrodes of their respective tubes so as to provide an electrostatic shield therebetween to minimize undesirable capacitance between the input and output circuits of the individual stages.

A source of space current indicated +B is coupled to the anode electrodes of the tubes through the inner windings of bifilar coils 88 and 93. Also, the tubes include heater circuits which are coupled to a suitable heater supply 'source through additional bifllar coils 99 and 99'. The bifllar coils 88, 93, 99 and 99' are included in the arrangement for the purpose of isolating the radio-frequency signals from the direct current sources. To this end, the outer bifilar windings of coils 88 and 93 shield the source of space current +B while the coils 99 and 99 provide suitable direct current heater circuits -and function as radio-frequency chokes with reference to signals translated through the individual stages. The unidentified condensers in the amplifying system are conventional by-pass condensers.

In the operation of the Fig. 6 arrangement, input signals applied to the cathode circuit of tube 89 are translated therethrough, being amplifled in conventional manner, and are applied to the cathode circuit of tube 8|, appearing after further amplification therein, in the output circuit including coaxial cable 95. In view of the described arrangement of the electrode leads and terminal prongs included in the tubes 89 and 8| and the conductive caps of their control electrodes, substantially all undesired capacitances between those portions of the input and output circuits provided by the tube elements are sub put and output circuits which are exclusive of thetube elements. It will be apparent, therefore, that the amplifying system is substantially free of undesired capacitances of the type under consideration and thus may operate efliciently over a wide band of operating frequencies, even in the ultra-high-frequency portion of the frequency spectrum.

An additional feature of the described arrangements resides in the high signal-to-noise ratios which are realized through the use of triode tubes.

While there have been described what are at present considered to be the preferred embodiments of this invention,- it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A triode type of cathode-input s gnal-translating arrangement comprising, an anode, a cathode, conductive elements connected to said anode and cathode, including electrode leads extending in the same direction, a single control electrode positioned between said anode and said cathode. and a conductive shield structure connected to said control electrode and positioned substantially intermediate all conductive elements connected to said anode and all conductive elements connected to said cathode, said shield struc ure compr ing at least one electrode lead extending in said direction.

2. A triode type of cathode-input signal-translating arrangement comprising. an anode, a cathode, lead-in structures connected to said anode and cathode extending in the same direction and comprising the only conductive elements connected to said anode and cathode, a single control electrode positioned between said anode and cathode. and a conductive shield structure connected to said control electrode comprising a lead-in structure extending in said direction and positioned substantially intermediate all of said lead-in structures of said anode and cathode.

3. A triode type of cathode-input signal-translating arrangement compris ng, a terminal structure including at least three closely spaced terminals arranged with one substantially intermediate the remaining two, an anode, a cathode, conductive elements connected to said anode and cathode, including an anode lead and a cathode lead extending in the same direction and connected with different ones of said two terminals, a single control electrode positioned between said anode and cathode, and a conductive shield structure connected to said control electrode and positioned substantially intermediate all conducl0 lating arrangement comprising, a terminal structure including at least four closely spaced terminals arranged with a first pair substantially intermediate a second pair, an anode, a" cathode, conductive elements connected to said anode and cathode, including an anode lead and a cathode lead extending in the same direction and connected with difierent ones of said second pair of terminals, 2. single control electrode positioned between said anode and cathode, and a'conductive shield structure connected to said control electrode and positioned substantially intermediate all conductive elements connected to said anode and all conductive elements connected to said cathode, said shield structure comprising a pair of electrode leads extending in said direction and connected with different ones of said first-pair of terminals.

5. A triode type of cathode-input signal-trans lating arrangement comprising, a terminal structure including at least four closely spaced terminals arranged with a first pair substantially intermediate a second pair, an anode, a cathode, conductive elements connected to said anode and cathode, including an anode lead and a cathode lead extending in the same direction and connected with diiferent ones of said second pair of terminals, a single control electrode positioned between said anode and cathode, and a conductive shield structure connected to said control electrode and positioned substantially intermediate all conductive elements connected to saidanode and all conductive elements connected to said cathode, said shield structure comprising a pair of electrode leads extending in said direction and connected with different ones of said first pair of terminals and at least one conductive plate interconnecting said pair of electrode leads throughout a major portion-of their lengths,

6. A triode type of cathode-input signal-translating arrangement comprising, a terminal structure including a plurality of closely spaced terminals arranged in approximately a circular pattern with two terminals substantially diametrically opposed, an anode, a cathode, conductive elements connected to said anode and cathode, including anode leads and cathode leads extending in the same direction and connected respectively with the terminals located on opposite sides of said two terminals, a single control electrode positioned between said anode and cathode, and a conductive shield structure connected to said control electrode and positioned substantially intermediate all conductive elements connected to said anode and all conductive elements connected to said cathodev said shield structure comprising two electrode leads extending in said direction and connected with dififerent ones of said two terminals.

7. A triode type of cathode-input signal translating arrangement having concentrically arranged electrodes comprising, a cylindrical anode, a cathode, conductive elements connected to said anode and cathode, including electrode leads extending in the same direction, a single cylindrical control electrode positioned between said anode and cathode, and a conductive shield structure connected to said control electrode and positioned substantially intermediate all conductive elements connected to said anode and all conductive elements connected to said cathode, said shield structure comprising at least one electrode lead extending in said direction.

8. A triode type of cathode-input signal-translating arrangement comprising, an anode, a.

cathode, conductive elements connected to said anode and cathode, including electrode leads extending in the same direction, a single control electrode positioned between said anode and cathode, and a conductive shield structure connected to said control electrode and positioned substantially intermediate all conductive eleanode from said cathode, said cathode and said said cathode lead and said anode lead.

ments connected to said anode and all conduc- 9. A'triode type of cathode-input signal-trans lating arrangement comprising, an anode, a cathode, conductive elements connected to said anode and cathode, including electrode leads extending in the same direction, a single control electrode positioned between said anode and cathode, and a conductive shield structure connected to said control electrode and positioned substantially intermediate all conductive elements connected to said anode and all conductive elements connected to said, cathode, said shield structure comprising at least one electrode lead extending in said direction and conductive plates extending from the opposite ends of said control electrode and projecting beyond the ends of sai anode and cathode.

10. A triode type of cathode-input signaltranslating arrangement comprising, an anode, a cathode, conductive elements connected to said anode and cathode, including electrode leads extending in the same direction, a single control electrode positioned between said anode and cathode, and a conductive shield structure connected to said control electrode and positioned substantially intermediate all conductive elements connected to said anode and all conductive elements connected to said cathode, said shield said press, said grid shield being connected to leads oppositely disposed across said press whereby the space between the press and said electrodes is divided into two shielded compartments.

12. An electron-discharge device having an envelope provided with a press at one end thereof, a plurality oi leads extending through said press, a mountwithin said envelope comprising a cathode, grid and anode supported on said leads, said grid being provided with shields for shielding said 13. An electron-discharge device having an envelope provided with a press atone end thereof, a plurality of leads arranged in a circle extending through said press, a mount within said envelope comprising alcathode, grid and anode supported on said leads, said grid having a shield for shielding said anode from said cathode, said cathode and said anode being connected to leads disposed on opposite sides of said circle, said grid shield being provided with connectors connected to leads on opposite sides of said circle, said last leads lying in a plane passing between said cathode lead and said anode lead.

14'. An electron-dischargedevice including an envelope having a press provided with a plurality of leads extending therethrough, a mount supported within said envelope and including a cathode, a grid surrounding said cathode, and an anode outside of said grid, a connector connected between the anode and a lead in said press, and a connector connected between said cathode and a lead in said press oppositely disposed to said lead connected to said anode, said grid being provided with a shield connected thereto and positioned between the press and said grid, said shield being provided with a skirt adjacent said anode lead for shielding said anode lead from said cathode lead, said shield being connected to other leads in said press, said other leads lying in a plane passing between the anode lead and the cathode lead.

HAROLD A. WHEELER.

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